1014 NOTES ON AUSTRALIAN EARTHWORMS, 



Perich^ta tenax, FL, I.e. (2), I. (1886), p. 953. 



Ten good average (spirit) specimens out of about thirty are 

 from 101-157 mm. long, 5-6 mm. broad; number of segments from 

 about 116-150. 



Setse : when all are in place 36 may be counted on the first 

 setigerous segment (ii), which number continues for some distance 

 until just behind the clitellum where 40 may often be counted; in 

 the posterior region except on the last few segments the number 

 may increase to about 50 or 60 ; fewer than the numbeis specified 

 may be met with in individual cases. 



Clitellum comprises segments xiv-xvii and part of xiii. 



Accessory copulatory structures : the characteristic structures 

 present on ix and x may extend outwards on each side as far as 

 the third or fourth setae {i.e., further out than previously men- 

 tioned) and in one case there is an additional one on xi ; they 

 vary somewhat in regard to the extent to which they are developed, 

 and occasionally extend only half-way (antero-posteriorly) across 

 the segment. In addition to these there are certain other struc- 

 tures often only represented by vaguely defined swellings ; on the 

 ventral surface of xvii and of xix is a pair of circular depressions, 

 one on either side of and not far from the median line and im- 

 mediately in front of a line joining the first (ventral) seta on each 

 side, each surrounded by a more or less circular tumid rim, the 

 two of each pair merely contiguous or more or less confluent ; and 

 often a single median one on xviii. In sexually mature worms 

 the papillse carrying the male pores are situated (in spirit speci- 

 mens) on the inner aspect (probably more evident owing to 

 shrinkage in the middle) of two much bigger swellings extending 

 antero-posteriorly across the segment, frequently pitted; in 

 immature worms one may find an earlier stage showing five 

 little pits with tumid surroundings forming an interrupted ridge, 

 of which the middle one persists without much alteration, the first 

 on each side of it being a male pore with its rudimentary papilla, 

 and the second eventually becoming so much developed as to 

 overshadow the papillae of the $ pores. 



